Zoom lenses employed in conventional cameras employ multiple lenses which must be moved relative to one another to obtain variation and magnification and for focusing. Typically a small electric motor is used to drive the lenses. It would be desirable to incorporate zoom lenses on small portable cameras, such as the type used with cellular phones, but the physical limitations of the small devices make the provision of a conventional zoom lens impossible. A better solution to the problem would be to provide a tunable liquid crystal lens. These lenses comprise a liquid crystal layer sandwiched between a pair of electrodes. By applying different voltages on the electrodes, the index of refraction of the lens may be varied to obtain different focal lengths.
Such liquid crystal lenses present attractive features for use with small portable cameras such as cell phone cameras. They have been under development for over 25 years and many advantageous structures have been proposed including nonhomogeneous nanoscale polymer dispersed LC droplets composing the LC layer. By exposing the LC layer to ultraviolet light, a selected lens pattern will be permanently created. The applied voltage on the electrodes will modify the refractive index profile of the lens. Ultraviolet treatment of the liquid crystal to form a desired pattern which may be varied by applying different voltage is also mentioned in “Cholesterol-oleate-doped polymer-dispersed liquid-crystal voltage-controlled ring projector”, by Olivares-Pérez et al., Optics Letters Vol. 27, No. 12, pages 1022-1024, Jun. 15, 2002.